linux-kernel - [PATCH v1 1/3] sched/debug: use int type and fix wrong print for rq->nr

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Date:   Wed, 12 Apr 2023 11:07:29 +0800
From:   "晏艳(采苓)" <yanyan.yan@...group.com>
To:     linux-kernel@...r.kernel.org
Cc:     "谈鉴锋" <henry.tjf@...group.com>,
        "晏艳(采苓)" <yanyan.yan@...group.com>,
        "Tiwei Bie" <tiwei.btw@...group.com>,
        "Ingo Molnar" <mingo@...hat.com>,
        "Peter Zijlstra" <peterz@...radead.org>,
        "Juri Lelli" <juri.lelli@...hat.com>,
        "Vincent Guittot" <vincent.guittot@...aro.org>,
        "Dietmar Eggemann" <dietmar.eggemann@....com>,
        "Steven Rostedt" <rostedt@...dmis.org>,
        "Ben Segall" <bsegall@...gle.com>, "Mel Gorman" <mgorman@...e.de>,
        "Daniel Bristot de Oliveira" <bristot@...hat.com>,
        "Valentin Schneider" <vschneid@...hat.com>
Subject: [PATCH v1 1/3] sched/debug: use int type and fix wrong print for rq->nr_uninterruptible

commit e6fe3f422be1 ("sched: Make multiple runqueue task counters
32-bit") changed rq->nr_uninterruptible from 'unsigned long'
to 'unsigned int', but left the wrong print to
/sys/kernel/debug/sched/debug and to the console.

For example:
Current type is 'unsigned int' and value is fffffff7, and the print
will run the sentences,
"do {                                    \
    if (sizeof(rq->x) == 4)                     \
        SEQ_printf(m, "  .%-30s: %ld\n", #x, (long)(rq->x));    \
    else                                \
        SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x));\
} while (0)"

The result will be 4294967287 on 64-bit machines to print (long)(rq->x)
while old type 'unsigned long' will print -9.

And the other places that use its value will cast to int to return
expected output, so we convert its type from 'unsigned int' to int.

Signed-off-by: Yan Yan <yanyan.yan@...group.com>
---
 kernel/sched/loadavg.c | 2 +-
 kernel/sched/sched.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
index 52c8f8226b0d..b9867495fe8b 100644
--- a/kernel/sched/loadavg.c
+++ b/kernel/sched/loadavg.c
@@ -80,7 +80,7 @@ long calc_load_fold_active(struct rq *this_rq, long adjust)
 	long nr_active, delta = 0;
 
 	nr_active = this_rq->nr_running - adjust;
-	nr_active += (int)this_rq->nr_uninterruptible;
+	nr_active += this_rq->nr_uninterruptible;
 
 	if (nr_active != this_rq->calc_load_active) {
 		delta = nr_active - this_rq->calc_load_active;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 060616944d7a..23c643948331 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1006,7 +1006,7 @@ struct rq {
 	 * one CPU and if it got migrated afterwards it may decrease
 	 * it on another CPU. Always updated under the runqueue lock:
 	 */
-	unsigned int		nr_uninterruptible;
+	int			nr_uninterruptible;
 
 	struct task_struct __rcu	*curr;
 	struct task_struct	*idle;
-- 
2.32.0.3.g01195cf9f